Method of fabricating implantable medical devices from a polymer coupon that is bonded to a rigid substrate

ABSTRACT

Plural medical device formed from one or more layers of thin film polymer are assembled from a single polymer coupon. Initially the coupon is bonded to a rigid substrate. Force, heat and a suction are selectively applied to the coupon to ensure that it has a consistent height across its exposed surface. Once the polymer coupon is bonded the components forming the medical device are attached to the coupon and the coupon is shaped to form the individual medical devices. Shaped sections of the coupon are then lifted off the rigid backing. The lifted off sections on which the components were attached are the medical devices.

RELATIONSHIP TO PRIORITY APPLICATIONS

This application is a divisional of U.S. patent application Ser. No.14/615,547 filed 6 Feb. 2017, now U.S. Pat. No. 9,700,262. application.Ser. No. 14/615,547 is a divisional of U.S. patent application Ser. No.14/080,259 filed 14 Nov. 2013 now U.S. Pat. No. 8,951,426. application.Ser. No. 14/080,259 is a continuation of PCT App. No. PCT/US2012/037888,filed 15 May 2012, now expired. PCT App. No. PCT/US2012/037888 is anon-provisional of U.S. Prov. Pat. App. No. 61/486,906 filed 17 May2011, now expired. The contents of the above-identified applicationsfrom which this application claims priority are incorporated herein byreference.

FIELD OF THE INVENTION

This invention relates generally to a method of manufacturingimplantable medical devices that include a substrate, intermediatelayers or a superstrate formed from a thin film polymer. Moreparticularly, this invention relates to a method of manufacturingimplantable electrode arrays that includes one or more thin film polymerlayers.

BACKGROUND OF THE INVENTION

There is an increasing interest in providing articles of manufacturethat include one or more layers support layers formed from a thin filmpolymer. A “thin film polymer” is understood to be a polymer having athickness of 1 mm or less. This polymer has found to be a good substrateor carrier layer on which electrically conductive traces can be formed.Also, this polymer, even though thin in cross section, has sufficientmechanical strength that it can also support the mounting of mechanical,electromechanical and electrical components. Another feature of thispolymer is that even though it is capable of supporting components andconductors, it is flexible. Thus, this polymer can serve as a substratefor an assembly that, owing to its intended use, may require componentsthat are disposed on a non-linear surface.

One such article of manufacture is an implantable medical device. Thesedevices are implanted into a living being, human or species, to performfor diagnostic and or therapeutic reasons. One such device is anelectrode array. This type of device includes some sort of carrier orframe on which plural exposed electrodes are mounted. Conductors, alsopart of the array, function as the array components over which currentsare sourced to or sunk from the individual electrodes. Some electrodearrays are further constructed so that the actual components from whichcurrent is sourced to or sunk from the array are also mounted to thearray. The array itself is designed for implantation against the tissueof a living being, including a human. More particularly, the array ispositioned so that electrodes are able to flow current through tissue sothat current flow will result in the desired physiological effect on thepatient. Selective current flow through a patient is used for or hasbeen proposed for the following therapeutic reasons: correcting cardiacarrhythmia; pain management; appetite suppression; control ofincontinence; and the overriding of damaged neurological connectionsthat have resulted in loss of muscle control and/or loss of feeling.Still another application of these arrays is to monitor the electricalimpulses generated by the individual's neurological system. Theelectrodes of the array transmit signals representative of theseelectrical impulses to components off the array. The off arraycomponents may are able to use these signals to control the devices towhich they are connected. These devices include, but are not limited to,mechanically powered exoskeleton units that move the individual, roboticlinkages and artificial speech generators.

The Applicant's Assignee's FOLDABLE, IMPLANTABLE ELECTRODE ARRAYASSEMBLY AND TOOL FOR IMPLANTING SAME, PCT Pub. WO 2009/11942 A2, U.S.patent. application. Ser. No. 12/873,397, US Pat. Pub. No. US2011/0077660 A1, its IMPLANTABLE ELECTRODE ARRAY ASSEMBLY INCLUDING ACARRIER FOR SUPPORTING THE ELECTRODES AND CONTROL MODULES FOR REGULATINGOPERATION OF THE ELECTRODES EMBEDDED IN THE CARRIER AND METHOD OF MAKINGSAME, PCT Pub. No. WO 2011/017426 A2, U.S. Pat. Pub. No. US 2012/0310316A1, the contents of which are incorporated herein by reference, discloseversions of these electrode arrays. Generally, the electrode arrays ofthese publications include a frame, sometimes called a carrier, formedfrom an elastic material. Electrodes are disposed over these frames. Theframes of these disclosures are formed from Nitinol, a nickel titaniumalloy. Given the conductive nature of these frames, it is necessary toform the electrodes themselves over electrically insulating layers.These documents state that it may be desirable to apply parylene-C tothe elastic Nitinol carrier so that this material, once cured, functionsas the insulating support layer. These documents actually state that itmay be desirable to apply plural layers of parylene. Each layer, oncecured, functions as the layer upon which one or more conductivecomponents are formed. For example, the cured parylene layers closest tothe elastic carrier serve as support layers on which conductors areformed. The outer layers of the parylene serve two functions. Firstthese layers serve as the electrically insulating skin of the array.Secondly, at least one of these parylene layers typically also functionsas the support layer over which the array electrodes are formed.

Parylene is a good electrical insulator, bonds well to superelasticmaterial like Nitinol, is flexible once cured and accepts metal layersthat are selectively etched to form conductors and electrodes. These aredesirable qualities for an insulating layer that is part of animplantable electrode array. However, parylene has been found to have acharacteristic that limits its suitable as an insulating layer for animplantable electrode array. Specifically, parylene absorbs relativelyhigh quantities of water. An electrode array implanted into livingtissue is surrounded by body fluids. These fluids are primarily water.Given the parylene tends to absorb water, there is a concern that, overtime, a significant quantity of these bodily fluids could be absorbedinto the parylene layers of the electrode array. This fluid, onceabsorbed into the parylene, can force the insulating layer to delaminatefrom the layers to which it is bonded. This delamination of theinsulating layer can, in turn, result in the breakage and subsequentmalfunctioning of the array itself.

Accordingly, there is an increasing interest in forming the insulatinglayers out of polymer other than parylene. One alternative polymer thatcan be employed in an electrode array as an electrically insulatinglayer is a liquid crystal polymer. This polymer, like parylene, has goodbonding properties, is flexible when bonded, and accepts metal layers.In comparison to parylene, a liquid crystal polymer absorbs appreciablyless water. Once implanted in a living being, the LCP insulating layeror layers of an electrode array absorb nominal amounts of body liquidand, by extension, are less prone to delaminate.

The Assignee's incorporated by reference PCT Pub. No. WO 2011/017426 A2,discloses that an electrode array with LCP insulating layers can beformed by first mounting some components to the array frame. Then thepolymer, in the liquid state, is applied to the partially assembledarray and allowed to cure. This method of assembly has been found to beexpensive. Accordingly, there is an interest in forming implantableelectrode arrays with liquid crystal polymer layers wherein the LCPitself is already in sheet form.

However, to date, it has proven difficult to manufacture electrodearrays with LCP that is already in the form of a cured sheet. This isbecause the sheets when applied to the frame or other layer over whichit is bonded often seats unevenly over the underlying surface. Thismakes it difficult, if not impossible, to then apply the metal layers onthe LCP insulation layer in a manner that ensures that conductive layersand/or electrodes remain bonded to the insulating layer.

SUMMARY OF THE INVENTION

This invention relates to a new and useful method of fabricating animplantable medical device that includes one or more layers supportlayers that is a thin, biocompatible polymer film. The method may beused to construct a device intended to provide a therapeutic effectand/or provide diagnostic information. Using this method, the device canbe manufactured that has a substrate, intermediate layer, superstrate orother support layer formed of polymer that has a thickness of 1 mm orless.

One such device that can be fabricated according to the method of thisinvention is an electrode array designed for implantation into livingtissue.

According to the method of this invention, the thin polymer film onwhich components are to be fabricated is initially applied to a backing.To perform this process, an adhesive is initially disposed on thesurface of the backing on which the polymer film is to be bound. A pieceof polymer film, 64 sometimes referred to as coupon, is applied to thebacking. Once the coupon is applied to the backing, pressure is appliedto the coupon while the assembly is at a temperature above ambienttemperature and a pressure below ambient pressure. The pressure ensuresthe bonding of the film to the adhesive coating on the backing. Further,the pressure ensures that that film is at a relatively constant heightabove the backing.

The components that provided the intended therapeutic effect and/ordiagnostic are the attached to the coupon. In some but not all versionsof the invention, this attachment process includes the selective etchingaway of sections of the coupon. If the components are conductive, theycan be attached to the coupon by selectively applying layers of metal tothe exposed face of the coupon. This metal can be applied to formconductors. If the assembly under formation is an electrode array,spaced apart sections of metal are applied to the coupon to for thearray electrodes. During the application of metal to the coupon, metalis sometimes deposited into the previously formed through openings inthe coupon. The metal in these openings later function as vias throughthe insulating layers formed by the coupons.

Other components that form part of the completed device assembly mayalso be bonded to the exposed face of the polymer. These componentsinclude electrical components such as integrated circuits. Supportmembers can also be mounted to the coupon. These support members includestructural components that provide the coupon with at least somerigidity. These support members include materials that may beplastically deformable such as plastic or metal frames. Alternatively,these support materials may be formed from material that has someelasticity, such as frame members formed from Nitinol.

The piece of the polymer film is shaped to define a section of the filmthat is the support layer for the device under assembly. This processmay be performed mechanically or electrically. Often, but not always,this process occurs before the below described removal, lift off, of thedevice from the backing.

In some constructions of the invention, one coupon to which componentshave been added may then be bonded to a second coupon. This process isperformed by inverting one of the backed coupons so the exposed face ofthe coupon is directed to the exposed face of the second backed coupon.The coupons are then placed together and bonded by thermal compressionbonding. Following the bonding of the coupons, the backing is releasedfrom one of the coupons. A new backed LCP layer may be bonded to thisnewly exposed face of the partially completed assembly.

As a consequence of the above processes, the work piece under assemblyconsists of plural LCP coupons that are bonded together. Conductors,other electrical components and structural members are sandwichedbetween these layers.

Once the multi-layer assembly is formed, some components may be attachedto the exposed face of the outermost LCP coupon. The bottommost couponis then released from the associated backing. Either before or afterthis process, the portions of the coupons that do not form the assemblyare separated from the layers forming the assembly.

This invention provides a means to form components on cured sections ofthin film polymer such as liquid crystal polymer films. During thisprocess of this invention, the film is held to the backing such that thefilm has a substantially uniform height above the backing. Consequently,the surface of the polymer coupon is essentially planar and free fromfolds and bumps. This increases the likelihood that the assembly,collectively the polymer coupon and the components applied to it, willbe structurally sound. Further, this invention provides a means to bondtwo polymer layers together. By extension, this invention provides ameans to fabricate assemblies formed from three or more layers of thinpolymer film. Components for obtaining diagnostic information orproviding a therapeutic effect may be bonded to one or more of theplural layers of this multi-layer assembly.

Still another feature of this invention is that it is possible tosimultaneously shape and process separate sections of a single backedpolymer coupon. Each coupon section can be shaped to have the featuresthat will be found in a separate assembly. Electrical components andstructural components can be applied to or placed on the individualsections of the coupon. The different sections of each coupon can beprocessed to form sections of separate assemblies under construction.Thus, this invention facilitates the batch processing of a thin polymerfilm so that the separate sections of the coupon form the layers ofseparate finished assemblies.

In this method assembly is the coupon is removed from the backing bydissolving the adhesive holding the coupon to the backing. Once theadhesive is dissolved, the polymer and attached components are subjectedto essentially no mechanical stress when lifted away from the backing.The essential elimination of this stress results in a like eliminationthat this stress could damage either the damage to the polymer supportlayer or the component(s) attached to the layer.

The processes of this method can be practiced together. Alternatively,it is a feature of this invention that the processes of this method can,is appropriate, be practiced independently from each other.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention is pointed out with particularity in the claims. The aboveand further features and advantages of the invention are understood fromthe following Detailed Description taken in conjunction with thefollowing drawings in which:

FIG. 1 illustrates an electrode array that is at least partiallyfabricated according to the method of this invention;

FIG. 1A is an enlarged view of the distal end of the electrode array ofFIG. 1.

FIG. 2 is a cross section view of the electrode array of FIG. 1;

FIG. 3 is a plan view of a coupon of this invention on which a number ofarray frames are formed;

FIG. 4 is an enlarged view of a section of the frame coupon of FIG. 3;

FIG. 5 is a cross sectional view along line 5-5 of FIG. 4 showing aportion of the frame coupon after there has been an application of anoxidation layer over selected surfaces of the frame coupon;

FIG. 6 is a side diagrammatic illustration of the placement of a LCPcoupon backing on a vacuum chuck;

FIG. 7 is a side diagrammatic illustration of the coating of adhesiveover the LCP coupon backing of FIG. 7;

FIG. 8 is the side diagrammatic depiction of the placement of the LCPcoupon and glass plate over the LCP coupon backing and the clamping ofthe coupon and glass plate to the press chuck

FIG. 9 is a side diagrammatic depiction of the pressing of the LCPcoupon to the backing;

FIG. 10 is a time line representation of the steps of the pressingprocess executed to bond an LCP coupon to the back;

FIG. 11 is a cross sectional view of the LCP coupon bonded to thebacking;

FIG. 12 is a side cross sectional view of a section the LCP coupon ofFIG. 11 after the coupon has been shaped to form an electrode arraypassive side layer;

FIG. 13 is a plan view of the frame coupon disposed over the LCP couponon which the electrode array passive side layers are formed;

FIG. 14 is a plan view of the individual frames disposed over the LCPcoupon on which the electrode array passive side layers are formed;

FIG. 15 is a cross sectional view of a portion of a frame mounted to theLCP coupon on which the electrode array passive side layers are formed;

FIG. 16 is a cross sectional view of the frame and LCP coupon of FIG. 15after a control module has been seated in the frame;

FIG. 17 is a cross sectional view of an LCP coupon from which arrayfirst intermediate LCP layers is formed immediately after the coupon isbonded to a backing;

FIG. 18 is a cross sectional view of the LCP coupon of FIG. 17 showingthe coupon after a recess has been formed to extend partially throughthe coupon;

FIG. 19 is a cross sectional view of the LCP coupon of FIG. 17 afterthrough openings have been formed in the coupon;

FIG. 20 is a cross sectional view of the LCP coupon of FIG. 19 aftermetal has been deposited in some of the openings to form cores thatextend through the coupon;

FIG. 21 is a plan view of the LCP coupon of FIG. 20 showing the pluralrecesses and slots formed in the coupon as well as the metal cores thatextend through the coupon;

FIG. 22 is cross sectional view of how the LCP coupon of Figures and 19and 20 is placed in registration over the LCP coupon and frame assemblyof FIG. 15;

FIG. 23 is a cross section view of the bonded LCP coupons of FIG. 22;

FIG. 24 is a cross sectional view of the bonded LCP coupons of FIG. 23after the backing attached to the topmost LCP coupon has been removed;

FIGS. 25, 26 and 27 are a sequence of cross sectional views depictingthe shaping of the LCP coupon on which plural array second intermediateLCP layers are fabricated;

FIG. 28 is a plan view of the LCP coupon of FIG. 27;

FIG. 29 is a cross sectional view of a portion of a partially assembledelectrode array being assembled according to the process of thisinvention after the LCP layer of FIGS. 27 and 28 is bonded to theassembly of FIG. 24;

FIGS. 30, 31 and 32 are a sequence of cross sectional views depictingthe shaping of the LCP coupon on which plural array third intermediateLCP layers are fabricated;

FIG. 33 is a cross sectional view of a partially assembled electrodearray being assembled according to the process of the invention afterthe LCP layer of FIG. 32 is bonded to the assembly of FIG. 29;

FIGS. 34 and 35 cross sectional views depicting the shaping of the LCPcoupon on which plural array active side LCP layers are formed;

FIG. 36 is a plan view of the LCP coupon of FIG. 35; and

FIG. 37 is a plan view of, as result of an alternative manufacturingprocess of this invention, the arrangement of plural separatearray-forming LCP layers on a common backing.

DETAILED DESCRIPTION I. An Electrode Array that can be AssembledAccording to this Invention

FIGS. 1, 1A and 2 illustrate an implantable medical device 50constructed according to the method of this invention. This device 50 isan electrode array and is referred to as such throughout the remainderthis document. Electrode array 50 includes a number of spaced apartelectrodes 52. In the illustrated version of the invention, theelectrodes 52 are arranged in a row by column pattern. Many electrodearrays 50 constructed using the method of this invention have at least10 electrodes. Still other electrode arrays constructed according tothis invention have 20 and even 40 or more electrodes. In the depictedversion of the invention, each electrode is rectangularly shaped. Thesize and shape of the electrodes 52 can vary with the function of thearray 50. Thus it should be understood that in some versions of theinvention, each electrode may have a width of 10 mm or less, 5 mm orless or in some applications, 2 mm or less. The length of an individualelectrode 52 may be 40 mm or less, 20 mm or less, 10 mm and less andeven 5 mm or less.

Array 50 also includes a number of control modules 54, one seen in FIG.2. Each control module 54 is connected to one or more electrodes 52.Each control module 54 is an application specific integrated circuit(ASIC). The circuit includes components able to source current from/sinkcurrent to the associated electrodes 52. In FIG. 2, the control module54 is shown disposed below the electrode 52 with which the module isassociated.

Conductors 56 and 58 (one of each shown) extend from the control modules54. Conductors 56 and 58 are connected to a cable 60 that extends fromthe proximal end of the electrode array assembly 50. (Here “proximal”means toward the end of the array 50 at the bottom of FIG. 1. “Distal”means toward the end of the assembly at the top of FIG. 1.) Notillustrated are the individual conductors internal to cable 60. Cable 60is connected to an implantable device controller (IDC) 62. The IDC 62contains the power source for the currents that are flowed between theelectrodes 42. IDC 62 also contains a controller that generates theinstructions that indicate between which electrodes 52 the currents areto be flowed. The structure of the IDC 62 is not part of the presentinvention.

Electrode array assembly 50 is shaped to have a base 66 that is the mostproximal portion of the assembly. Nine rows of electrodes 52 are locatedforward of base 66. Each row of electrodes 52 is longitudinally spacedfrom the adjacent row (or rows) of electrodes. This spacing is oftenbetween 0.5 and 10 mm. In the illustrated version of the invention,there are six electrodes 52 in each row of electrodes. The array 50 isconstructed so that the inner four electrodes 52 in each row are eachseated on a separate rectangularly shaped tab 68. Eachelectrode-carrying tab 68 is separated on three sides from thesurrounding portions of the array 50. More particularly, interleavedwith each row of electrodes 52 are two I-shaped slots 70. Each slot 70thus defines the perimeters of two tabs 68. In some versions of theinvention, slots 70 are shaped so that each tab 68 has a length(measurement along an axis parallel to the longitudinal axis of assembly50) of between 0.5 to 5 mm. Often this length is between 2 and 4 mm.Each tab 68 has a width, (measurement along the axis perpendicular tothe longitudinal axis of assembly 50 in the plane of FIG. 2) of 0.25 to2 mm. In many versions of the invention, this width is between 0.5 to 1mm. The distance across each slot 70 is approximately 75 microns. Array50 is thus formed to have two columns of I-shaped slots 70. Within eachrow of electrodes 52, the two slots 70 are spaced laterally apart fromeach other and are laterally aligned with each other.

Immediately forward of the distal most row of electrodes 52 array 50 isformed to have a head 74. Head 74 is the most distal portion of thearray 50. The head 74 is shaped to have an arcuately shaped leadingedge. The arc forming this leading edge is centered on the longitudinalaxis that extends along the array. On each side of the front edge, thehead 74 is shaped to have an edge that, is as it extends proximally awayfrom the distal end, extends away from the array longitudinal axis.

Array head 74 is formed to have two slots 76. Slots 74 are locatedopposed sides and symmetric relative to the array longitudinal axis.Each slot 76 forms a number of sections. Specifically each slot 76 has abase section 78 that is parallel to and laterally offset from the arraylongitudinal axis. More particularly each slot base section 76 is inregistration with a separate one of the rows of slots 70. The mostforward portion of each slot section 76 opens into a primary opening 80.Each primary opening 80 is generally in the form of a triangle. The mostacute apex of opening 80 is directed towards the most distal end of thehead 74. Each slot 76 is further formed to have a distally directedextension 82. Each distal extension 82 extends forward from the apex ofthe slot primary opening 80. From the associated slot primary opening80, each slot distal extension 82 curves both distally forward andtowards the longitudinal center axis of the array 50. While the slotdistal extensions 82 curve towards each other, the extensions do notconnect.

As illustrated by FIG. 2, embedded in and part of the electrode array 50is a frame 88. Frame 88 is formed from a superelastic material.Superelastic material is material that, after being subjected to thestrain induced by appreciable rolling, folding or bending, returns toits initial shape. In one version of the invention, the frame 88 isformed from a nickel titanium alloy such as Nitinol. As seen best inFIG. 4, frame 88 is formed from a single piece of Nitinol and is shapedto have a proximal located tail 90. Frame 88 also has a head 130 that isspaced forward of tail 90. Three parallel spaced apart bridges 114, 116and 118, extend from the frame tail 90 towards the frame head 130.

Frame tail 90 includes two beams 92 and 112 that extend perpendicularlyto the longitudinal axis of the array 40. Beam 92, the more proximal ofthe two beams, is the shorter of the two beams. Beam 112, is longer thanand is located distal to beam 92. Both beams 92 and 112 are centered onthe longitudinal axis of the array 40. A number of additional beams arelocated between beams 92 and 112. Two beams 96 and 102 extend betweenbeams 92 and 112. Beams 96 and 102 are perpendicular to beams 92 and 112and extend along axes parallel to the longitudinal axis of frame 88.Another beam, beam 94 extends distally and outward from a side of beam96 to the adjacent end of beam 112. A beam 104 extends outwardly anddistally forward from a side of beam 102 to the adjacent end of beam112. The location along beam 96 from which beam 94 extends distallyforward is forward of the location along beam 102 from which beam 104extends. A beam 106, that is parallel to beam 92, extends between beams96 and 102. Beam 106 extends perpendicularly outwardly from beam 102from approximately the location along beam 102 from which beam 104extends distally forward.

Bridges 114, 116 and 118 extend distally forward from beam 112. Bridge116 is centered along the longitudinal axis of the frame 88. Bridges 114and 118 are spaced apart symmetrically relative to bridge 116. A numberof three-sided tabs 120 extend outwardly from bridges 114, 116 and 118.Frame 88 is shaped so that tabs 120 have major axes that are parallel tothe longitudinal axis of the frame. Tabs 120 are arranged in pairs;where a tab 120 extends outwardly from one side of a bridge 114, 116 or118, a laterally aligned tab 120 extends outwardly from the opposed sideof the same bridge. The tabs 120 are further so that, where the tabsextend outwardly from one bridge 114, 116 and 118, tabs also extendoutwardly from the laterally adjacent sections of the other two bridges.Frame 88 is therefore constructed so that the tabs 120 are arranged inrows wherein, in the illustrated version of the invention, there are sixtabs in each row. The rows of tabs 120 are longitudinally spaced apartfrom each other.

In some versions of the invention, frame 88 is shaped so that the tabs120 have a length, distance along the axis parallel to the longitudinalaxis of the frame 88, of between approximately 0.5 and 4.0 mm. The widthof the tabs 120, the distance the tab extends away from the associatedbridge 114, 116 or 118, of between approximately 0.5 and 2.0 mm. Theframe 88 is formed so that each row of tabs 50 is spaced approximately0.5 to 4.0 mm away from the row of laterally adjacent tabs. It should befurther understood that frame 88 is further shaped so that each tab 120that extends outwardly from center located bridge 116 is spaced awayfrom the adjacent tab that extends outwardly from the adjacent bridge114 or 118. This separation is typically a minimum of 100 microns.

Frame 88 is further formed so that each tab 120 is shaped to have acenter located rectangular opening 122. The major axes of the tabopenings 122 are, centered on the major axes of the tabs 120. Eachopening 122 is dimensioned to receive an individual control module 54.Also the outermost tabs 120, the tabs that extend outwardly from theouter side edges of bridges 114 and 118, have tapered front and rearsections, the sections perpendicular to the longitudinal axis of theframe. These sections (not identified) are tapered so that that lengthof the tab 120 decreases slightly as the tab extends away from thebridge 114 or 118 with which the tab is integral. The outer corners ofthe tabs (corners not identified) are rounded.

A number of rectangularly shaped beams 124, also part of frame 88,connect bridges 114, 116 and 118 together. The frame 88 is shaped sothat, where a beam 124 extends between bridge 114 and bridge 116, alaterally adjacent beam 124 extends between bridge 116 and bridge 118.The beams 124 are arranged so that a pair of laterally adjacent beams islocated immediately in front of and rearward of all but the mostproximal row of tabs 120. A pair of beams 124 are located immediatelyforward of the most proximal row of tabs 120. In the illustrated versionof the invention, there are nine rows of tabs; accordingly there are 18pairs of laterally adjacent beams. Each beam 124 has a width, thedistance parallel to the longitudinal axis of the frame 88, which istypically 2.0 mm or less, and often 0.5 mm or less.

As described above, the tabs 120 that extend outwardly from bridge 116are spaced away from the adjacent tabs 120 integral with bridges 114 and118. The tabs 120 are spaced longitudinally away from the adjacent interbridge beams 124. Thus, between bridges 114 and 116 and between bridges116 and 118 there are I-shaped slots 123 around the tabs 120. Asdiscussed below the void of each slot 123 is the primary void of aseparate one of the array slots 70. Thus, each frame slot 123 has shapesubstantially identical to an array slot 70. Each frame slot 123 has awidth that is approximately 25 microns wider than an array slot 70.

Frame head 130 is formed to have two slots, slots 132. The void of eachslot 132 is the primary void of a separate one of the array slots 76.Accordingly, each slot 132 has a shape that corresponds to the shape ofthe corresponding arrays slot 76.

Returning to FIG. 2 it can be seen that layers of liquid crystal polymer(LCP) insulating material are disposed around the opposed surfaces offrame 88. One layer of LCP, LCP layer 136, is disposed over the passiveside of the frame 88 and the control modules 54 encased in the frame.(The “passive” side of the array/frame is the side opposite the side onwhich the electrodes 52 are disposed. The “active” side of thearray/frame is the side on which the electrodes 52 are disposed.) Theouter surface of LCP layer 136 thus functions as the passive side faceof the array 50. A first intermediate LCP layer, LCP layer 138, isdisposed over the active side of frame 88 and embedded control modules54. Where the passive side surface of LCP layer 138 is not disposedagainst the control modules 54 or frame 88 this surface is disposed overlayer 136. A second intermediate LCP layer, layer 140, is disposed overthe active side surface of first intermediate LCP layer 138. A thirdintermediate LCP layer, layer 142, is disposed over the active sidesurface of second intermediate LCP layer 140. An active side LCP layer,layer 144, is disposed of the active side surface of third intermediateLCP layer 142. The outer surface of LCP layer 144 functions as theactive side exposed face of the array 50.

The electrodes 52 are embedded in the active side LCP layer 144. Onelayer of conductors, specifically conductors 56, are embedded in thesecond intermediate LCP layer 140. A second layer of conductors,specifically conductors 58, are embedded in the third intermediate LCPlayer, 142. Vias 146 are formed in and extend through LCP intermediatelayer 138 between the control modules 54 and conductors 56. Vias 148 areformed in and extend through LCP intermediate layers 138 and 140 betweencontrol modules 54 and conductors 58. Vias 146 and 148 thus provide theelectrical connections between the control module 54 and, respectively,conductors 56 and 58. Plural vias 150 are formed in and extend throughintermediate LCP layers 138, 140 and 142. Each via 150 provides anelectrical connection from the control module 54 to the electrode 52with which the module is associated.

II. Method of Assembly

The assembly of the electrode array 50, actually the batch assembly ofplural arrays 50, starts with the fabrication of plural frames 88.Frames 88 are fabricated by shaping a sheet section of the material fromwhich the frames are formed. This sheet is known as a coupon 160, seenin FIG. 3. In the described version of the invention coupon 160 isformed from Nitinol and has a thickness between 25 and 100 microns. Morespecifically, frame coupon 160 has a thickness that is approximately 10microns greater than the height of the control modules 54 disposed inthe frames 88.

Using a chemical etch processes, portions of the coupon 160 are removedto define a number of through openings. Prior to the etching of thecoupon, the coupon sections that are to remain parts of the frame aremasked to prevent their removal. The openings in the coupon 160 definedin this etching process include through openings that define both theouter perimeter of plural frames 88 as well as the structural featuresof each frame. The perimeter the outer shape of an individual frame isdefined by a slot 162 seen in FIG. 4. The width of the slot 162 variesalong the perimeter of the associate frame 88 so as to define the outershape of the frame. For example, where a tab 120 extends outwardly fromone of the bridges 114 or 118, slot 162 is of narrow width. Adjacent thetab-free portions of bridges 114 and 118, slot 162 has a wider width.

In this etching step, each slot 162 is formed so as to not completelysever the frame 88 defined by the slot from the surrounding portion ofthe coupon. Instead the slot 162 is broken into sections by a number ofretaining tabs 164. Each tab 164 (one seen in FIG. 4A) extends betweenthe frame 88 with which the tab is integral and a section of the coupon160 that surrounds the frame. While only one tab 164 is seen in FIG. 4A,typically plural tabs 164 extend between each frame 88 and the rest ofthe coupon 160. In the described version of the invention there are twotabs 164. The tabs 164 are centered on opposed of the longitudinalcenter axis of the frame 88 with which the tabs are associated.

In some versions of the invention, plural etching or other materialremoval processes are performed on the coupon 160 in order to define theframes 88. One reason to perform the plural etching processes is toshape the coupon 160 so that the tabs 164 have thickness less than thethickness of the portions of the coupon 160 that have not been removed.In some versions of the invention, these plural etching processes areperformed so that the tabs 164 have thicknesses that are approximately30 to 70% of the thickness of the unetched coupon sections.

After the Nitinol coupon 160 is shaped, oxide is deposited on theportions of the coupon that form the frames 88. This process isperformed by first masking off the portions of the coupon 160 that willnot function as array frames 88. This mask is often a photo-resistresin. After the masking, the coupon is placed in a chamber and siliconoxide is deposited on the unmasked portion of the coupon. The oxide isdeposited by a plasma enhanced chemical vapor deposition process. Thesilicon oxide coats the unmasked portions of the coupon as seen in FIG.5. The silicon oxide coating, called out as layer 163 in FIGS. 5 and 15,has a thickness of approximately 1000 to 10,000 Angstroms. In someversions of the invention the coating is more often between 1,500 and4000 Angstroms.

After the coupon 160 is shaped to define the frames 88, the coupon maybe further shaped to bend the frames. This processing is performed ifthe array 50 is designed for application over tissue that is not planar.In this instance, the frames, while still part of coupon 160, arepermanently bent so as to approximate the shape of the surface of thetissue to which the assembly arrays 50 are applied. For example, ifarrays 50 are intended for application over the spinal cord, each frame88 is shaped so that, on each side of its longitudinal axis, the framecurves out of the plane of the coupon 160. Not illustrated is adepiction of the frames 88 extending out of the plane of the coupon 160.

Frame shaping may be performed by pressing the coupon 160 betweenopposed dies. Each die has geometric features that bend the attachedframes 88 into the desired shape. Once the frames 88 are so pressed,heat is applied to set the frames 88. The heat may be sourced fromheaters in the individual dies, external heaters or heat transferredfrom liquid surrounding the dies. As a consequence of the simultaneousbending and heating of the frame 88, the carriers develop the desiredcurved shape, undergo the desired plastic deformation.

An LCP coupon, coupon 176, first seen in FIG. 8, is shaped to define theplural passive side LCP layers 136 to which the frames 88 are bonded. Asdepicted by FIG. 6, this process starts with the placement of a backing172 on a vacuum chuck 170. A vacuum chuck is a chuck to which an objectsuch as the wafer can be held using a suction drawn and that can spin.This particular vacuum chuck 170 is, as discussed below, rotated atspeeds up to 10,000 RPM. Backing 172 is formed from a rigid materialable to withstand the below described processing steps withoutfracturing. In one version of this invention backing 172 is siliconwafer generally in the shape of a circle with a slice section at one endremoved. The backing 172 may have a diameter of 150 mm and a thicknessof 500 microns.

Once backing 172 is disposed on chuck 170, an adhesive 174 is evenlyapplied to the exposed face of the backing, as represented by FIG. 7.One such adhesive that is applied to backing 172 is a formed from ablend of phthalic anhydride and ethanediol sold under the trade markCRYSTALBOND by electron Microscopy Services of Hatfield, Pa., US. Toensure that the adhesive 176 is evenly applied to the backing 172, oncethe adhesive is applied to the backing, chuck 170 is rotated.Specifically, chuck 170 is initially rotated at a speed of approximately500 RPM for approximately 10 seconds. This rotation of chuck 170 and, byextension backing 172 and adhesive 174, roughly spreads the adhesiveover the whole of the backing. Chuck 170 is that rotated at a speed ofbetween 1,000 to 3,000 RPM for approximately 5 to 20 seconds. Thisrotation of the backing 172 and the adhesive 174 evenly spreads theadhesive over the whole of the backing. These spin steps are performedat room temperature. At the end of these steps, the exposed face ofbacking 172 is coated with a layer of adhesive 174 that is approximately1 to 5 microns thick. The adhesive 174 is disposed over the backing 172so that there is a variation in its thickness of less than 1%.

After adhesive 174 is evenly spread over backing 172, the backing isseated on a press chuck 175 represented in FIG. 8 by a block.

After the backing 172 is transferred to the press, adhesive 174 isapplied to backing 172, the LCP coupon 176 is applied to the exposedsurface of the adhesive as represented by FIG. 8. The coupon 176 has athickness of 50 microns. LCP coupon 176 has a shape that approximatesthe shape of backing 172. Coupon 176 has a surface area that is greaterthan the surface area of the support layers, layers 136 that the couponis shaped to form. Coupon also has a surface area that is less than thesurface area of the backing 172. Specifically, LCP coupon 176 is shapedso that when the coupon is applied to the adhesive 174, the outerperimeter of the coupon is recessed approximately 5 to 50 micronsinwardly from the outer perimeter of backing 172. For purposes ofillustration, this difference in surface areas is exaggerated in thedrawings

As also represented by FIG. 8, a glass plate 178 is disposed over theLCP coupon 176. Plate 178 has a thickness of between 0.5 to 3.0 cm.Glass plate 178 has a surface area such that the plate extends beyondthe outer perimeter of both backing 172 and coupon 178. Moreparticularly, while not seen in FIGS. 8 and 9, plate 178 extends atleast 0.5 cm beyond the perimeter of backing 172. Clamps 180, (twoshown), extend from the exposed surface of the glass coupon to presschuck 175. Clamps 180 thus hold glass plate 178 both to press chuck 175and over LCP coupon 176. The clamped assembly is then transferred to abond chamber 182, the pressure of which can be controlled. In FIG. 9,bond chamber 182 is represented by the background rectangle.

Once the clamped assembly is positioned within the bond chamber 182, apiston head 184, seen in FIG. 9, is pressed against the exposed face ofthe glass plate 178. Piston head 184 is urged against glass plate so asto apply a force of approximately 3000 Newtons. As represented by FIG.10, almost immediately after the forcing of piston head 184 againstplate 178, a suction is drawn on chamber 182 to lower the pressure. Inone version of this invention, the pressure in chamber 182 is lowered to10⁻⁴ bar. It takes approximately 10 minutes to lower chamber pressure tothis pressure. During these steps, chamber temperature is maintained atambient levels, represented in FIG. 10 by 20° C.

Once the pressure in chamber 182 falls to the target level, thetemperature in the chamber is raised while maintaining the pressure onplate 178. In one version of this invention, chamber temperature israised to approximately 125° C. It takes approximately 5 to 10 minutesfor the chamber temperature to rise to this level. Once the chambertemperature reaches the target level, chamber temperature and pressureare maintained while maintaining the press force on the plate 178 andthe underlying LCP coupon 176. In some versions of the invention, theassembly is maintained at this state for a period ranging between 10 and30 minutes. After this period of maintaining constant temperature andpressure, the temperature is allowed to drop towards back to ambientlevels. After approximately 10 to 20 minutes, the temperatures will havedropped to 70° C. Once the temperature has fallen to this level,pressure in vacuum chamber 182 is allowed to rise to ambient levels.Once the pressure in chamber 182 rises to ambient level, press head 182is retracted away from plate 178 a sufficient distance to allow theclamped assembly to be removed from vacuum chamber 182, (step notshown).

Clamps 180 are removed. Glass plate 178 is lifted off the LCP coupon176. The backing-adhesive-LCP coupon assembly is lifted of press chuck175. (Steps not illustrated). At this time, as represented by FIG. 11,the LCP coupon 176 is firmly attached to the backing 172 by adhesive 174as represented by FIG. 11. As a result of the pressing under vacuum andheat process, the outer surface of the coupon 176 is of uniform heightover the backing 172. Here “uniform height” is understood that theheight of the surface of the LCP coupon 176 above backing 172 varies byless than 5% and more preferably 1.5% or less.

LCP coupon 176 is now ready for addition processing so that one seriesof steps, the coupon can be shaped to form plural array passive side LCPlayers 136. In this process, portions of the coupon 176 are selectivelyremoved. This process is performed by first applying a photo resist overthe portions of the coupon 176 through which slots are not to be formed.Then, in an oxygen plasma reactive ion etching (O2 Plasma RIE) process,the unmasked portions of the LCP coupon are removed. The mask materialis then removed from the remaining sections of the coupon 176. The abovesteps are performed while the coupon 176 remains bonded to backing 172.As a result of these processes coupon 176 now appears as depicted inFIG. 12. In this Figure LCP coupon is substantially as it appeared inFIG. 11. Now though, as seen in FIG. 12, a number of slots, two slots184 and 186 shown, extend through the coupon 176. As will be clear fromthe following description and subsequent drawings, each of the slotsformed in LCP coupon 176 become a section of one of the slots 70 and 76that extend through the array 50. Slots 184 and 186, for example, aresections of the top and bottom sections of one of the tab 68-definingslots 70. In other words it will be seen that, as the array 50 is built,one of the ASIC-embedded and electrode carrying tabs will be built upbetween slots 184 and 186.

In the next series of steps, the frame coupon 160 is bonded to theexposed face of the LCP coupon 176. To prepare the LCP coupon 176 forthe actual bonding, this surface is exposed to oxygen plasma. Thisexposure in a vacuum chamber. This exposure to the oxygen plasmaroughens the surface of the LCP coupon. This exposure is for a periodapproximately 20 minutes.

Once the surface of the LCP coupon 176 is so roughened, frame coupon 160is positioned over the LCP coupon 176. Specifically the frame coupon 160is so positioned so that the frame coupon slots 123 and 132 are inregistration over the complementary slots formed in the LCP coupon 176.This is seen in FIG. 15, wherein the opposed parallel sections of onethe frame coupon I-slots 123 is in registration over the LCP couponslots 184 and 186. In FIG. 13, the extent to which the outer perimeterof LCP coupon 176 is inwardly recessed from back 172 and the extent towhich the outer perimeter of the frame coupon 160 is inwardly recessedfrom the outer perimeter of the LCP coupon are exaggerated for purposesof illustration.

To perform the actual frames to LCP coupon bonding, the multi-layerassembly is placed in a vacuum pressure chamber. A piston is disposedagainst the Nitinol coupon while under a vacuum of approximately 0.1mBar. The piston force is between 500 and 3000 Newtons and typicallybetween 700 and 1500 Newtons. The chamber is heated to a temperaturebetween 200 and 300° C. This is the temperature range at which thesurface of LCP coupon 176 becomes semi-liquid. Under these conditions,the semi-liquid LCP of coupon 176 embeds into the silicon oxide roughedportions of the frame coupon 160. Thus, upon completion of this process,the silicon oxide roughed portions of the frame coupon 160 areinterlocked with, bonded to, the underlying sections of the LCP coupon.The oxide-free portions of the Nitinol coupon 160 are smoother than thenthe oxide coated portions of the coupon 160. Consequently during thisthermal compression bonding process, the LCP of the coupon 176 do notinterlock or bond with these oxide-free sections of sections of framecoupon 160.

Once the frames 88 are bonded to LCP coupon 176, the sections of theframe coupon 160 not part of the frames is lifted off the LCP coupon176. This process is performed first mechanically serving the tabs 164(FIG. 4) from the frames 88. The remnants of coupon 160 are manuallylifted off the LCP coupon 176.

As a result of the lifting off of the remnants of the frame coupon 160from the LCP coupon 176, the partially assembly arrays appear as inFIGS. 14 and 15. The plural frames 88 are bonded to the LCP coupon 176.FIG. 15 represents a section of one frame 88. More particularly, FIG. 15is a cross section through a single tab 120 adjacent beams 124 of asingle frame 88. The tab opening 122 it is observed is disposed over anunderlying section of the frame forming LCP coupon 176. Owing to theplacement of the frames 88 on the LCP coupon 176, each one of the LCPcoupon slots 184 and 186 is located below and between the frame tab 120and an adjacent frame beam 124.

As represented by FIG. 16, the next step in the batch assembly of theelectrode arrays 50 is the placement of the control modules 54 in thetab openings 122. The oxide coating 163 disposed around thewindow-defining faces of each frame 88 electrically insulates thecontrol modules 54 from the frame.

Prior to the first intermediate LCP layers, LCP layers 138, beingapplied over the frames 88, these layers 138 are fabricated a LCPcoupon, coupon 196 in FIG. 17. LCP coupon 196 is formed from the samematerial as LCP coupon 176. LCP coupon 196 has a thickness of 75 to 150microns. To process LCP coupon 196, coupon 196, like coupon 176, isplaced on a backing, backing 192 in FIG. 17. An adhesive layer, layer194 holds LCP coupon 196 to backing 192. The same processes used toaffix LCP coupon 176 to backing 172 are used to affix LCP coupon 196 tobacking 192. Accordingly these process steps will not be redescribed. Itshould likewise be understood that these process steps are used tosecure below described LCP coupons 224, 244, and 266 to, respectively,backings 220, 240, and 262.

After LCP coupon 196 is attached to backing 192, plural recesses 198 areformed in the coupon 196. Each recess 198 does not extend all the waythrough coupon 196. Instead each recess 198 extends inwardly from theouter surface of the coupon to a depth at least equal to the thicknessof the frames 88. Recesses 198 are formed in LCP coupon 196 by firstmasking over the portions of the coupon 196 on which the recesses arenot to be formed. Then, using the oxygen plasma RIE process, recessesare formed in the unmasked portions of the coupon 196. The aluminum maskis then removed. As seen best in FIG. 21, each recess 196 has an outlinewith a shape identical to the perimeter of the frame 88 over which thecoupon 196 will subsequently be disposed. In terms of dimensions eachrecess 196 has a surface area that, at a minimum, corresponds to thesurface area of the frame 88 subsequently fitted in the recess. Recesses196 have a depth that, at a minimum, is equal to the thickness of theframes 88.

After recesses 198 are formed in LCP coupon 196, the coupon is subjectedto a second oxygen plasma RIE process. This etching process is executedto form a number of openings. These openings, seen in FIG. 19, extendfrom the base of the recesses 198 completely through the rest of the LCPcoupon 196. A number of these openings are slots, represented by slots202 and 210 in FIGS. 19 and 21 and slots 212 in FIG. 21. Upon assemblyof the arrays 50, these slots 202, 210 and 212 slots become part of thearray slots 70 and 76. Specifically, slots 202 and 210 are differentsections of a single one of the array I-shaped slots 70. Each slot 212becomes a part of an array slot 76.

In this second etch process, a second set of openings, through bores204, 206 and 208 are also formed in the LCP coupon 196. Each throughbore 204 is generally circular in cross section and has a diameter ofbetween 5 to 1000 microns and often 50 to 250 microns.

The next step in the fabrication of the plural first intermediate LCPlayers 138 is the filling of through bores 204, 206 and 208 withconductive material as seen by FIG. 20. Metal, often gold, is depositedin through bores 204, 206 and 208. In one process for depositing thisgold, first a thin layer of titanium, approximately 500 Angstroms thickis applied by a sputtering process over the whole of the coupon 196.This titanium adheres to the inner cylindrical walls of the LCP coupon196 that define the bores 204, 206 and 208. A gold layer, also ofapproximately 1000 Angstroms thick, is then applied by a sputteringprocess to the whole of the coupon 196 over the titanium. It should beappreciated that this titanium layer is initially applied becausetitanium adheres well to both LCP and gold.

Once the thin gold layer is applied, gold is then plated only in bores204, 206 and 208. To perform this plating, the coupon is masked so thatonly bores 204, 206 and 208 are exposed. The gold is then applied by anelectroplating process so as to file the bore. In this process, thepreviously applied gold functions as a seed layer to which theelectroplated gold bonds. The gold covered mask layer is removed. Thenthe thin layers of titanium and gold that cover the rest of the couponare removed.

As will be apparent from the following description, the metal in bores204 functions as the array vias 146 between the control module andconductor 56. The metal cores in bores 206 function as sections of thearray vias 148 that extend between the control module and conductor 58.The metal cores in bores 208 function as sections of the array vias 150that extend between the control module 54 and the overlying electrode52. In FIG. 20, these metal cores are identified using theidentification numbers of the vias that they eventually become.

With the addition of the via-forming metal, LCP coupon 196 appears as inFIGS. 20 and 21. Specifically, the coupon 196 has a number of recesses198. Each recess 198 is shaped to receive a separate frame 88. A numberof slots 202 210 and 212, extend from the base of each recess 198,through the polymer, to the opposed face of the coupon 196, the facebonded to the adhesive layer 194. The slots correspond to sections ofthe array slots. Specifically, each pair of slots 202 and 210 is part ofone of the array I-shaped slots 70. Slots 212 are part of the slots 76located in the array head. Plural metal columns, each represented inFIG. 21 by a black dot, extend from the base of each recess 198 to theopposed face of the coupon 196.

Once LCP coupon 196 is formed to define the plural LCP intermediatelayers 138, the coupon 196, while still attached to backing 192 isinverted (step not shown). The inverted coupon 196 is then placed inregistration over LCP coupon 176. More specifically as seen in FIG. 22,the two coupons 176 and 196 are aligned so that each recess 198 ofcoupon 196 is in registration over one of the frame 88.

The LCP coupon 196 is then placed against LCP coupon 176 as seen by FIG.23. In this step, the frames 88 and the control modules 54 fitted in theframes, seat in the recesses 198. The outer surfaces of LCP coupons 176and 196 abut. It should be appreciated that, as result of where the viaforming metal columns are present in the LCP coupon 196, these metalcolumns seat over and abut the bond pads of the control modules 54.(Control module bond pads not illustrated.)

During these steps of inverting LCP coupon 196 and positioning thecoupon 196 over coupon 176 it should be appreciated that the chuck thatit is positioning the coupon 196 is actually holding onto backing 192.

Once the LCP coupons 176 and 196 are pressed together, the coupons arebonded together by a thermally induced pressure bond. In this processthe LCP on the faces of the opposed coupons 176 and 196 becomesemi-liquid and adhere together to form a unitary structure. Forpurposes of understanding the invention, these plural LCP coupons, and,by extension, plural array LCP layers, are illustrated as separatelayers.

After the LCP coupons 176 and 196 are bonded together, backing 192 islifted off of LCP coupon 196. This process is performed by placing theassembly in an empty bath so that backing 192 is exposed down, againstthe base of the bath. The bath is filled with a sufficient volume ofacetone to cover backing 192 but below the backing 172. The assembly isallowed to sit in the acetone until the acetone dissolves adhesive layer194. Typically this takes anywhere from 10 to 30 minutes. As a result ofthe dissolving of the adhesive layer, the assembly, minus backing 192can then be removed from the bath. Acetone remaining on the assembly isthen removed by rinsing the assembly in isopropyl alcohol. The assemblyis then subjected to a drying process. This process is performed byplacing the assembly in a sealed oven, flooding the oven with nitrogengas and raising the oven temperature to 80° C. The heat causes theacetone to evaporate off the assembly.

Once the assembly is removed from the oven, the assembly appears asdepicted in FIG. 24. The control modules 54 and frames 88 are embeddedbetween the coupons that form LCP coupons 176 and 196. LCP coupon 176,the coupon forming layers 136, remains bonded to backing 132. Theportions of vias 146, 148 and 150 that extend through the LCP coupon 196extend through this coupon.

An LCP coupon, coupon 224, in FIG. 25, is shaped to form the pluralsecond intermediate LCP layers 140. Coupon 224 has a thickness ofbetween 10 and 50 microns. The previously described bonding steps areused to secure coupon 224 to its complementary backing, backing 220 inFIG. 25. Here it can be seen that adhesive layer 222 holds LCP coupon224 to backing 220. LCP coupon 224 has a thickness of 10 to 50 microns.Not shown is the depiction of LCP coupon 224 after it is thermalcompression bonded to the backing 220. As this drawing would essentiallybe the same as FIG. 17 which shows LCP coupon 196 after being pressbonded to backing 192, this drawing is omitted.

After LCP coupon 224 is bonded to backing 192, a series of grooves 228(one shown) are etched in the exposed face of the coupon. Grooves 228are formed on the LCP coupon 224 so as to have the pattern of theconductors 56. Grooves 228 are formed using the etching steps used toform recesses 198 in LCP coupon 196. The grooves 228 are formed to havea depth of 5 to 15 microns relative to the exposed face of the LCPcoupon 224. Grooves 228 have a generally rectangular cross sectionalsshape.

LCP coupon 224 is also shaped to form a number of openings seen in FIG.26. One type of opening formed in LCP coupon are slots, represented byslots 226 and 234. The slots are sections of the array slots 70 and 76.Thus, coupon slots 226 and 234 are each different sections of what uponcomplete assembly of the array 50 is one of the I-shaped slots 70. Slotsections 226 and 234 of LCP coupon 224 are essentially identical to slotsections 202 and 210 of LCP coupon 196.

The second type of openings formed in LCP coupon 224 are the openingsthrough which the conductors forming sections of vias 148 and 150extend. In FIG. 26, these openings are through bores 230 and 232.Through bores 230 and 232 are thus analogues to, respectively, throughbores 206 and 208 formed in LCP coupon 196. Bores 230 and 232 have thesame shape and cross sectional dimensions as, respectively, bores 296and 208.

In a series of steps, metal is first deposited in bores 230 and 232 andthen in grooves 228. Initially a titanium adhesion layer and gold seedlayer are deposited over the whole of the coupon 224. These layers havethe same thickness as the previously described versions of these layers.Then a photo resist mask is placed over the LCP coupon 224. The onlyportions of the coupon 224 left exposed by this mask are the openingsinto bores 230 and 232. An electroplating process is then used to fillbores 230 and 232 with gold. The next step in this process is theremoval of this first mask. A second mask is then applied to coupon 224.This mask is applied so as to leave exposed the outlines of the grooves228. The coupon 224 is then subjected to a second electroplatingprocess. In this process, gold is applied to fill the grooves 228. Uponcompletion of this electroplating process, the mask and underlying goldand titanium layers are removed. Here it should be understood that firstelectroplating process is performed to ensure that the gold rises to thetop of the bores 230 and 232. The second electroplating process isperformed to ensure that the face of the plated gold in the grooves 226is essentially uniform with the exposed face of the LCP coupon 224.

As a consequence of the selective plating of the coupon 224, the couponappears as in FIGS. 27 and 28. The gold fills grooves 228. These goldstripes are the conductors 56 and are identified as such. Gold cores aredisposed in bores 230 and 232. These cores are sections of vias 148 and150 and are identified as such. FIG. 28 depicts the exposed face of LCPcoupon 224. The face of LCP coupon 224 is planar since it will abut theexposed planar face of LCP coupon 196. Dashed lines 236 are on the faceof the LCP coupon 224 represent the perimeters of the individual LCPintermediate sections 140 eventually formed by different sections of thecoupon. Within each section of the LCP coupon 224 defined by one of theboarders there are three primary branches of conductor 56. Branchesextend from a trunk conductor not illustrated but also formed on thedefined section of the LCP coupon 224. A number of secondary branchconductors extend off each primary branch. Also shown in within thedefined sections of LCP coupon 224 are plural pairs of dots. These dotsrepresent the heads of the partially formed vias 148 and 150.

Once LCP coupon 224 is fabricated the coupon, while still attached tobacking 220, is inverted. LCP coupon is positioned over LCP coupon 196.Specifically, LCP coupon is positioned so that: LCP coupon 224 slotsections 226 and 234 are in registration of LCP coupon 196 slot sections202 and 210; conductors 56 in registration over vias 146; and viasections 146 and 150 of LCP coupon 224 and in registration with thecorresponding via sections in LCP coupon 176. The same process stepsused to bond LCP coupon 196 to LCP coupon 176 is used to bond LCP coupon224 to LCP coupon 176. As the steps for inverting and positioning andbonding LCP coupon 196 are essentially identical to the same processsteps used to bond LCP coupon 176, illustrations of these steps are notrepeated.

Once LCP coupon 224 is bonded to LCP coupon 196, backing 220 is liftedoff of coupon 224. The same process steps used to remove backing 192 offof coupon 196 are used to lift off backing 220. At the end of theseprocess steps, a number of partially assembled electrode arrays 50 aredisposed on backing 172. FIG. 29 illustrates a portion of one such array50. Here, control module 54 is disposed in a frame tab 120. The tab 120and adjacent beams 124 are disposed between LCP coupons 176 and 196that, respectively, form layers 136 and 138. The LCP coupon 224 thatforms the plural second intermediate LCP layers 140 is disposed over LCPcoupon 196.

An LCP coupon 244, seen in FIG. 30, is then subjected to processing toform plural third intermediate LCP layers 142. LCP coupon 24 has athickness similar to that of coupon 224. Initially. LCP coupon 244 isbonded to a backing 240 using the previously described LCP-to-backingbonding steps. While not illustrated, after these bonding steps itshould be understood that the resultant structure is similar if notidentical to the backing 172 and LCP coupon assembly of FIG. 17. A layerof adhesive, layer 242, holds coupon 244 to backing 240.

Plural grooves 248, one seen in FIG. 30, are then formed in LCP coupon244. Grooves 248 are essentially identical in cross sectional geometryand in width and depth dimensions to grooves 228 integral with LCPcoupon 244. Grooves 248 are the void spaces internal to the LCP coupon244 in which the metal forming array conductors 58 is subsequently bedeposited. The grooves 248 are therefore formed in LCP coupon 244 in thelocations where the conductors 58 need to be present.

Once grooves 248 are formed in LCP coupon 244, plural openings,illustrated best in FIG. 31, are formed in the coupon. Some of theseopens are slots. These slots are sections of the slots 70 and 76 thatextend through the individual array. In FIG. 31, slot sections 246 and252 are illustrated. Slot sections 246 and 252 are portions of one ofthe I-shaped slots 70 that extends through the array.

The other type of openings formed in LCP coupon 244 are through bores250 (one shown). Through bores 250 receive the deposits of metal that,upon formation of the arrays 50 becomes portions of the vias 150.

Once the openings are formed in the coupon, the metal is deposited inthe grooves 248 and bores 250. The same process steps used to depositmetal in the grooves 228 and bore 230 and 232 of LCP coupon 224 are usedto deposit metal in grooves 248 and bores 250 of LCP coupon 224. Theresults of the depositing of this metal are depicted in FIG. 32. Themetal deposited in grooves 248 will function as the conductors 58 and istherefore identified as such. The metal cores that form in bores 250function as sections of the vias 150 and are identified as such.

Once LCP coupon 244 is fabricated the coupon, while still attached tobacking 240, is inverted. LCP coupon 244 is positioned over LCP coupon224. Specifically, LCP coupon 244 is positioned so that: LCP coupon 224slot sections 246 and 252 are in registration of LCP coupon 224 slotsections 226 and 234; conductors 58 in registration over vias 148; andvia sections 256 off LCP coupon 244 and in registration with viasections 238 in LCP coupon 224. The same process steps used to bond theother LCP coupons together are employed to bond LCP coupon 244 to LCPcoupon 224. As the steps for inverting and positioning and bonding LCPcoupon 196 are essentially identical to the previously described LCPinverting, positioning and bonding steps illustrations of these stepsare not repeated.

Backing 240 is then lifted off LCP coupon 244 using the previouslydescribed backing lift off process. At this time, the partiallyassembled electrode arrays 50 remain bonded to backing 172. As seen byFIG. 33, the partially assembled electrode arrays at this time includean LCP layer not present in the partially assembled array of FIG. 29.Specifically, the LCP coupon 244, which forms the third intermediate LCPlayers 142 is now disposed over coupon 224, the coupon forming thesecond intermediate LCP layers 140. Embedded in the LCP layers 142 arethe conductors 58 and portions of the vias 150.

An LCP coupon 266, seen in FIG. 34, is shaped to form the plural activeside LCP layers 144. Coupon 266 is at least 50 microns thick. Tofacilitate the processing of coupon 266, the coupon is first bonded tobacking 262 by adhesive layer 264.

Once the LCP coupon 266 is fixed to backing 262, plural rectangularlyshaped recesses and openings are formed in the coupon as depicted inFIG. 34. These recesses and openings are formed in plural oxygen plasmaRIE processes. In a first oxygen plasma reactive ion etching processslots are formed in the coupon 266 to extend completely through thecoupon. In FIG. 34 these slots are represented by slots 270 and 276.Upon assembly of each array 50, the through slots 270 and 276 becomesections of the slots 70 and 76 that extend through the array. In thesecond etching process, rectangular recesses 272, one shown, are formedin LCP coupon 266. Each recess 272 functions as the void space wherein,in a subsequent step, metal forming the base pad of each electrode 52 isdeposited. Thus, in the second etching process, the recesses 272 areformed so as to have a shape and dimensions that correspond to the shapeand dimensions of the array electrodes 52. Recesses 276 are formed so asto have a depth of approximately 5 to 40 microns. The third oxygenplasma RIE process is executed to form through openings 274 that extenddownwardly from the bases of the recesses 270. Each through opening 274has a diameter of between 10 to 300 microns and is typically circular incross-sectional shape. Each through opening 274 extends from the base ofthe recess 266 from which the opening extends to the opposed face of thecoupon 266, the face bonded to backing 262.

Metal is then deposited in recesses 272 and openings 274 to form theelectrodes 52. An initial step in this process is the masking of thecoupon 266. The only sections of the coupon left mask-free are theopenings into through openings 274. Iridium is then deposited by asputter process into the through openings 274. The iridium is not,however, deposited to fill the whole of the openings 274. Instead, theiridium is deposited only partially fills the openings from the face ofthe coupon 266 disposed against backing 262. The top 5 to 10 microns ofeach opening 274 is not filled. Then, while the mask remains in place,titanium is sputter deposited on the coupon 266 to fill the openings274. Each through opening thus includes a column of metal, the lowerportion of which is iridium, the upper section of which is titanium.Each of these metal columns is considered a button 282 of the electrode52 with which the column is integral. In FIG. 35, where an electrode isillustrated, the plural layers of metal forming each button 282 are notillustrated.

Once the electrode buttons 282 are formed the first mask is removed. Atitanium adhesion layer approximately 500 Angstroms thick is appliedover the whole of the LCP coupon 266. A gold seed layer, of the samethickness as the titanium adhesion layer, is the applied over thetitanium layer. A second mask is then applied to the coupon 266. Theonly sections of the coupon 266 left exposed by the second mask are theopenings into the recesses 272. Gold is then electroplated to the LCPcoupon 266 to fill the recesses. The mask and the gold and titaniumdisposed underneath the mask are then removed.

Upon removal of the mask, gold and titanium, the electrodes 52 can beconsidered fabricated. One electrode 52 is seen in FIG. 35. Theelectrode includes a gold base pad 280, the gold in the recess LCPcoupon has the recess 272. A number of buttons 282 extend from the basepad through the LCP underlying the base pad to the exposed face of thepolymer coupon 266. The exposed faces the iridium cores that form thebuttons 282 are the actual exposed surfaces of the electrode 52. Buttonsare formed to have iridium faces because iridium provides a good lowimpedance interface against the living tissue against which the array 50is disposed. The titanium sections of buttons 282 are present becausethe titanium adheres well to iridium, liquid crystal polymer and gold.

The LCP coupon 266 thus appears as depicted in FIG. 36. In FIG. 36dashed lines 284 identify the perimeters of the array active side LCPlayers 144 formed by the coupon 266. The face of the coupon 266 isplanar. A number of slots extend through the coupon 266. In FIG. 36 onlytwo slot sections, slot sections 270 and 276 are identified. Uponmanufacture of the array 50, these slots become sections of the arrayslots 70 and 76. Also visible on the exposed face of LCP coupon 266 arethe exposed surfaces of the electrode base pads 280.

After the LCP coupon 266 is shaped and the metal layers deposited, thecoupon 266 is bonded to the exposed face of LCP coupon 224. While stillattached to backing 262, LCP coupon 266 and positioned over LCP coupon224. LCP coupon 266 is positioned against LCP coupon 224 so that thegold base pad 280 of each electrode 52 is disposed against the exposedface of the complementary via 150. LCP coupon 266 is then bonded to LCPcoupon 224 by the previously described thermal induced compressionbonding process. As a consequence of this bonding, vias 150 bond to thebase pads 280 of the overlying electrodes 56. Backing 262 is then liftedoff from LCP coupon 266 using the previously described backing lift offprocess. At this stage in the process of assembling the plural electrodearrays 50, an array in cross section would appear in the assembled statedepicted in FIG. 2.

At this stage in the electrode array assembly process, the pluralelectrode arrays 50 remain bonded to backing 172. The arrays 50 are eachpart of a laminate structure formed by the stacked LCP coupons 176, 196,224, 244 and 266. Prior to removal of the electrode arrays from thebacking 172, cuts are made in the LCP laminate to separate the arraysfrom the surrounding sections of the laminate. These cuts are made by apress.

Once the arrays 50 are defined on the backing 172, the arrays areremoved from backing and surrounding remnant LCP laminate. This step isperformed by using the previously described backing lift off process todissolve the adhesive 174 holding the arrays to the backing. The arraysare then dried, cleaned and tested for use.

Post manufacture of the electrode array assembly 50 there aresubstantial portions of the assembly that consist of the stacked layersof LCP film, layers 136, 138, 140, 142 and 144 that are stacked one ontop of the other. There are no electrical components, conductors orsupport members are disposed between these layers. These LCP filmlaminates form the form the body of the array that projects from theframe 88. Portions of this body can be considered membranes that extendover the sections of the array in which the frame 88 is embedded.Returning to FIG. 1A, two such membranes, membranes 302 are the LCP filmlaminate sections that extend between longitudinally adjacent spacedapart frame tabs 120 that extend outwardly from frame bridges 114 and118. In FIG. 1A dashed lines outline portions of the frame 88 disposedwithin the LCP film laminate body of the array. Other membranes,membranes 304, extend in the rectangular spaces between the bridges 114,116, 118 and beams 124.

Also while not show it should be appreciated that within frame slots 123and 132 the adjacent LCP layers 136 and 140 overlap the frame slots byat least 25 microns. These LCP layers cover the exposed interior sideedges of the frame 88.

As mentioned above the frames 88 internal to each array 50 may have beenshaped prior to their bonding to LCP coupon 176. If the frames 88 wereso shaped, each frame 88 upon lift off of the associated array returnsto its pre-flattened non-planar shape. This causes the array 50 withwhich each frame 88 is integral to develop a shape that generallycorresponds to that of the array.

This invention thus provides a means to assembly small implantableelectrode arrays out of a liquid crystal polymer. This material is thin,flexible and able to support electrical components. Moreover, incomparison to other polymers, liquid crystal polymer is less prone toabsorb water. Each of these features makes liquid crystal polymer wellsuited as a substrate or superstrate material for devices such aselectrode arrays intend for implantation against or into living tissue.

This invention also does more than provide a means to assemble electrodearrays out of liquid crystal polymer. The invention provides a means tosimultaneously batch assembly plural arrays out of this polymer. Thisability to batch assemble plural arrays assists in reducing the costs ofthe manufacture of these arrays.

III. Alternative Embodiments

The method of forming an assembly of this invention is described withreference to the fabricated assembly being an electrode array. It shouldbe understood that this method of fabricating assemblies that includethin polymer support layers of this invention may be used to fabricatemedical assemblies other than electrode arrays that provide either atherapeutic benefit or diagnostic information. Also, while the inventionis described as a means for assembling medical devices, that isimplanted in living tissue, use of this invention is not so limited. Theinvention may also be employed to construct medical devices intended forskin or surface tissue attachment.

Likewise, the invention need not only be employed to construct medicaldevices. Such devices include but are not limited to: transducers forbiological or mechanical sensing; display panels; circuit assembliesthat, post fabrication need to have non-planer shapes. Likewise, whilethe disclosed assemblies contain plural thin polymer layers, the methodof this invention may be used to fabricate assemblies that have only asingle layer of polymer. In versions of the invention not intended forbiological or medical use, it may not be necessary to employ abiocompatible polymer as the polymer that forms the device supportlayer.

Likewise, while many electrode arrays fabricated according to thisinvention will have plural electrodes, the method of this invention isnot limited to fabricating electrode arrays with plural electrodes. Themethod of this invention may be used to fabricate an electrode assemblythat only has a single electrode.

Similarly, the method of this invention may be used to assembly devicesthat do not include many features of the described electrode arrays. Forexample a device assembled according to this invention may not haveframe or frame members that provide some stiffness to the assembleddevice. Devices assembled according to this invention may havestiffening members different from the described single piece frames 88.For example, the frame may consist of a number of structural membersthat are not connected to each other. This type of frame may bedesirable when the end goal is the fabrication of a device that has somesections that are relatively flexible and other sections that have lessflexibility.

It should similarly be appreciated that the devices assembled employingthis method may include components that provide a therapeutic benefitand/or diagnostic information that are not electrically conductive. Forexample, the device may include structural members that resistcompression. These versions of the device may function as stents. Stillother versions of the device may include components that are embeddedwith a pharmaceutical agent. Once the device is implanted in the livingtissue, the pharmaceutical agent is released.

Likewise, the material from which the frame members are formed may bedifferent than the disclosed Nitinol. Thus, if it is desirable that theframe members be less elastic or less, flexible plastic or metals otherthan Nitinol may be used as frame members.

This invention may be used to fabricate electrical devices that includeintegrated circuits and discrete components that are directly mounted toa surface of one of the polymer layers. In these versions of theinvention, it may be necessary to form openings in the exposed surfaceof the polymer support layer prior to mounting the component thatprovided the therapeutic benefit or diagnostic information to thesupport layer.

Similarly, it should be appreciated that the described order of theprocess steps is exemplary, not mandatory. For example, in an optimalversion of this invention, it would most likely be best to first shapethe frame coupon 160 and the LCP coupons 176, 196, 224, 248 and 266before assembling the coupons together to form the laminate assembly.Likewise, the sequence of the steps performed to shape the individualLCP coupons may vary from what has been described. For example, if anLCP coupon is to include layers that contain both through slots andconductors the following sequence of steps may be used to fabricate thecoupon. First the through openings and or grooves and recesses in whichthe conductive material is to be deposited is formed. Then, theconductive material is deposited in these openings, grooves and/orrecesses. After these processing steps any additional openings thatextend either partially or completely through the LCP coupon are formed.These sequence of processing steps may be performed if it is technicallyefficient to, prior to the forming of any openings or recesses in whichmetal is not to be deposited, mask the deposited metal.

Similarly, the metal may be deposited on the LCP coupons using processesdifferent from what has been disclosed. For example, a different processfrom what has been described above with respect to FIGS. 35 and 36 maybe used to form the electrodes. In this process, the iridium cores aredeposited in the coupon through openings 274 in the steps describedabove. The mask covering the coupon 266 is then removed. Once the maskis removed, titanium is sputtered over the whole of the coupon 266, thistitanium, which is applied to a thickness of 5 to 10 microns and moreoften 7 to 9 microns, fills the unfilled portions of the coupon openings274. This titanium also coats the surfaces of the liquid crystal polymerforming the bases of the recesses 272. A seed layer of goldapproximately 500 Angstroms thick is deposited over the whole of thetitanium layer. The coupon 266 is masked so as to cover the couponexcept the openings into the recesses 272. Gold is then sputterdeposited over the coupon so as to form the electrode base pads 282.

Also, there may be versions of the invention wherein it is desirable tofirst attach at least some of the functional components to the supportlayer. After these components are attached, the components that increasethe rigidity of the layer, the Nitinol frame, or similar stiffeningcomponent, is attached to the layer.

Similarly other means may be employed to define the individual electrodearrays 50 on the backing that serves as the primary backing upon whichthe arrays are built. In the Figures, this is backing 172. For example,in one alternative version of the invention, instead of cutting away theunused sections of the LCP laminate from around the arrays, theseportions of the laminate may be etched away.

Likewise, in some versions of the invention, the steps of shaping eachLCP coupon to define features of the individual array LCP layers mayfurther include the shaping of the coupon to define the outer perimetersof the LCP layers. Once this shaping is performed, disposed on each oncethe coupon are plural spaced apart LCP layers. This is depicted in FIG.37. This depicts what one would see if LCP coupon 224 where fabricatedaccording to this process. Here, instead of the whole of the couponbeing attached to backing 220, the plural spaced apart, fully formedsecond intermediate LCP layers 140 are bonded to the backing 220. Alsoleft of the backing after the LCP etching process are LCP pads 233. Thepads 233 are spaced from the LCP layers 140. During the subsequent LCPlayer-to-LCP layer bonding process, the pads 233 first abut and thenbond to like LCP pads that extend upwardly from the underlying backing172. This pad-against-pad abutment prevents excessive flexure of thebackings during the bonding process.

The invention is described for use in fabricating assemblies formed outof polymer layers having a thickness of 1 mm or less. In describedversion of the invention, the polymer layers have thickness of 500microns or less. While the invention is described as being very usefulfor fabricating assemblies out of thin film liquid crystal polymer themethod of this invention is not so limited. The invention may be used tofabricate an assembly on flexible substrates or superstrates that arethicker than the above described LCP sheets. Likewise the assembly maybe used to fabricate assemblies on support layers such as substrates orsuperstrates formed from material other than liquid crystal polymer.Biocompatible polymers include in this class of materials includesilicone, parylene, polyamide and polymers other than liquid crystalpolymers. Devices wherein the biocompatible support layer is a thin filmcomposite structures that include one or more polymer components mayalso be constructed using the method of this invention. Thesecomposites, in addition to polymer, include material such as silicon andmetal. It should likewise be appreciated that this invention may be usedto manufacture assemblies wherein the polymer support layers are formedfrom different types of polymers.

Likewise there is no requirement that in all versions of the inventionpressure bonding be employed to bond the multi-layer forming polymercoupons together. Depending on the device being fabricated and thematerial forming the polymer coupons, biocompatible adhesives may beused to bond the coupons together. This adhesive may or may not bepressure set.

Further, the device assembled according to this invention may not be acomplete device. The device assembled according to this invention may bea sub-assembly of a device that includes additional components.

Accordingly, it is an object of the appended claims to cover all suchvariations and modifications that come within the true spirit and scopeof this invention.

What is claimed is:
 1. A method of assembling a medical device forimplantation on or in a living being, said method including the stepsof: bonding a first flexible polymer coupon formed from biocompatiblematerial to a first rigid backing, said bonding step including thesub-steps of: applying an adhesive layer to an exposed face of the rigidbacking; placing the polymer coupon on the adhesive layer; and applyingpressure to the polymer coupon to cause the coupon to bond to theadhesive layer wherein, as a result of said bonding step, the firstpolymer coupon has an exposed face that is opposite the first rigidbacking; attaching a component to a the exposed face of a section of thecoupon, the component able to provide a therapeutic benefit and/or offerdiagnostic information; while the first flexible polymer coupon remainsattached to the first rigid backing, selectively shaping the coupon sothat the section of the coupon to which the therapeutic or diagnosticcomponent is attached is smaller is area than the whole of the coupon;and dissolving the adhesive layer between the first polymer coupon andthe first rigid backing; and after said step of dissolving the adhesivelayer, lifting off the section of the first polymer coupon to which thetherapeutic or diagnostic component is attached from the first rigidbacking, the lifted off section of the first polymer coupon forming themedical device.
 2. The method of assembling a medical device forimplantation of any one of claim 1, wherein: in said step of attachingthe therapeutic or diagnostic component to the first polymer coupon,plural therapeutic or diagnostic components are attached to the couponso as to be spaced apart from each other; in said step of selectivelyshaping the first polymer coupon the coupon is shaped to form pluralsections, each section having at least one of the therapeutic ordiagnostic components mounted to the section; and in said adhesivedissolving step, dissolving the adhesive between the plural sections ofthe polymer coupon and the first rigid backing so that, in said lift offstep, the plural polymer sections with attached therapeutic ordiagnostic component are lifted off from the first rigid backing.
 3. Themethod of assembling a medical device for implantation of claim 1,wherein: after the first polymer coupon is bonded to the first backing,forming an opening that extends inwardly from the exposed surface of thefirst polymer coupon; and in said step of attaching the component to thecoupon, the component is at least partially seated in the opening formedin the coupon.
 4. The method of assembling a medical device forimplantation of claim 3, wherein, in said step of forming the opening inthe first polymer coupon, forming the opening so that the opening doesnot extend completely through the coupon.
 5. The method of assembling amedical device for implantation of claim 1, further including the stepsof: bonding a second flexible polymer coupon (196) to a second rigidbacking using said bonding step used to bond the first flexible polymercoupon to the first rigid backing wherein, as a result of said bondingstep, the second polymer coupon has an exposed face opposite the secondrigid backing; bonding the exposed faces of the first and second polymercoupons together to form a multilayer structure; and dissolving theadhesive layer between the second flexible polymer coupon and the secondrigid backing to remove the second rigid backing from the second polymercoupon.
 6. The method of assembling a medical device for implantation ofclaim 5, wherein: after said step of dissolving the adhesive layerbetween the second flexible polymer coupon and the second rigid backing,selectively shaping the multilayer structure; and after shaping themultilayer structure, performing said step of dissolving the adhesivelayer between the first flexible polymer layer and the first rigidbacking.
 7. The method of assembling a medical device for implantationof claim 1, further including the steps of: prior to said step ofdissolving the adhesive layer between first polymer coupon and the firstrigid backing, mounting a stiffening component to the first polymercoupon; and in said step of shaping the first polymer coupon, shapingthe coupon so that the section of the coupon to which the therapeutic ordiagnostic component is attached includes the stiffening component. 8.The method of assembling a medical device for implantation of claim 7,wherein the stiffening component is elastic.
 9. The method of assemblinga medical device for implantation of claim 1, wherein said step ofselectively shaping the first coupon is performed after said step ofattaching the therapeutic or diagnostic device to the first coupon. 10.The method of assembling a medical device for implantation of claim 1,wherein said step of selectively shaping the first coupon is performedby selectively cutting the coupon.
 11. The method of assembling amedical device for implantation of claim 1, wherein said step ofselectively shaping the first coupon is performed by etching awaysections of the coupon to define the section of the coupon with theattached therapeutic or diagnostic component.
 12. The method ofassembling a medical device for implantation of claim 1, wherein in,said step of apply adhesive to the first rigid backing the adhesive is aapplied so the variation in thickness of the adhesive layer is adhesivehas a maximum thickness of 5 microns and variation in thickness of lessthan 1%.
 13. The method of assembling a medical device for implantationof claim 1, wherein during said step of applying pressure to the firstpolymer coupon to bond the coupon to the adhesive layer, the pressurewhile the coupon and the first rigid backing are in a chamber in which asuction is drawn.
 14. The method of assembling a medical device forimplantation of claim 1, wherein the first polymer coupon has a maximumthickness of 1 mm.
 15. The method of assembling a medical device forimplantation of claim 1, wherein the first polymer coupon is from one ofthe group consisting of: liquid crystal polymer; silicone; parylene;polyamide; and composite structures that include at least one polymer.16. The method of assembling a medical device for implantation of claim1, wherein the assembled device includes plural electrodes.
 17. A methodof assembling a medical device for implantation on or in a living being,said method including the steps of: bonding a first flexible polymercoupon formed from biocompatible material to a first rigid backing, saidbonding step including the sub-steps of: applying an adhesive layer toan exposed face of the rigid backing; placing the polymer coupon on theadhesive layer; and applying pressure to the polymer coupon to cause thecoupon to bond to the adhesive layer wherein, as a result of saidbonding step, the first polymer coupon has an exposed face that isopposite the first rigid backing; bonding a second flexible polymercoupon formed from biocompatible material to a second rigid backingusing said bonding step used to bond the first flexible polymer couponto the first rigid backing wherein, as a result of said bonding step,the second polymer coupon has an exposed face opposite the second rigidbacking; attaching a component to the exposed face of at least one ofthe polymer coupons, the component able to provide a therapeutic benefitand/or offer diagnostic information; bonding the exposed faces of thefirst and second polymer coupons together to form a multilayerstructure; dissolving the adhesive layer between the second of thepolymer coupons and the second rigid backing so as to separate themultilayer structure from the rigid backing; dissolving the adhesivelayer between the first polymer coupon and the associated rigid backing;and after said step of dissolving the adhesive layer between the firstpolymer coupon and the first rigid backing, lifting off the multilayerstructure to which the therapeutic or diagnostic component is attachedfrom the rigid backing, the lifted off multi-layer structure forming themedical device.
 18. The method of assembling a medical device forimplantation of claim 17, wherein: in said step of attaching thetherapeutic or diagnostic component, the component is attached to thefirst polymer coupon so as to extend upwardly from the exposed surfaceof the coupon; while said second polymer coupon is bonded to the secondrigid backing, forming an opening the coupon that extends inwardly fromthe exposed surface of the coupon; and prior to said step of bonding thepolymer coupons together, placing the coupons in registration so thatthe therapeutic or diagnostic component seats in the opening formed inthe second polymer coupon.
 19. The method of assembling a medical devicefor implantation of claim 17, wherein in said step of forming theopening in the second polymer coupon, forming the opening so at least aportion of the opening does not extend completely through the secondpolymer coupon.
 20. The method of assembling a medical device forimplantation of claim 17, wherein: in a first execution said step ofattaching a therapeutic or diagnostic component to one of said coupons,a first electrically conductive component is attached the first polymercoupon so that the component has conductive surface adjacent the exposedface of the first polymer coupon; in a second execution said step ofattaching a therapeutic or diagnostic component to one of said coupons,a second electrically conductive component is attached the secondpolymer coupon so that the component has conductive surface adjacent theexposed face of the second polymer coupon; and prior to said step ofbonding the polymer coupons together, placing the coupons inregistration so that conductive surface of the first polymer coupon isin registration with the conductive surface of the second polymer couponso that, after the polymer coupons are bonded together, there is anelectrical connection between the first electrically conductivecomponent and the second electrically conductive component.